Tadalafil belongs to a group of medicines, known as phosphodiesterase-5 (PDE-5) inhibitors, which are used to treat erectile dysfunction or pulmonary arterial hypertension. Tadalafil is used to treat men who have erectile dysfunction (also called sexual impotence). Tadalafil belongs to a group of medicines called phosphodiesterase 5 (PDE5) inhibitors. Tadalafil relaxes muscles of the blood vessels and increases blood flow to particular areas of the body. Tadalafil under the name of Cialis is used to treat erectile dysfunction (impotence) and symptoms of benign prostatic hypertrophy (enlarged prostate). Tadalafil is FDA -approved for males as a therapy to treat and prevent symptoms of benign prostatic hyperplasia, such as urinary urgency, hesitancy, weak stream, dribbling, and incontinence. Tadalafil is a generic medication used to treat erectile dysfunction (ED), benign prostatic hyperplasia (BPH), and pulmonary arterial hypertension (PAH) in adults. Tadalafil (Cialis) is used for erectile dysfunction (ED) and benign prostatic hyperplasia (BPH) in adults. It belongs to the drug class called phosphodiesterase 5 (PDE-5) inhibitors. Tadalafil is a phosphodiesterase inhibitor used for treating impotence (erectile dysfunction, or ED), benign prostatic hyperplasia (BPH), and pulmonary arterial hypertension (PAH). Cialis (tadalafil) is a phosphodiesterase-5 (PDE5) inhibitor approved by the FDA to treat erectile dysfunction (ED) and benign prostatic hyperplasia (BPH). You can take Cialis daily in low doses. Deciphers the medication tadalafil (Adcirca, Cialis), a drug used for the treatment of impotence (erectile dysfunction, ED). Dosage, side effects, and drug interaction information is provided. Tadalafil is a medication prescribed to treat erectile dysfunction (ED). The drug increases blood flow to the penis during sexual stimulation.